I don't agree or disagree with your characterization of Hyperloop's true costs and risks because I'm not familiar enough with technical details, and because of that I'm curious what your basis is for your assertions.
You're using the "analysis by analogy" approach, where you say that this is the largest vacuum vessel ever built, and that there are some unspecified safety costs, and that together these necessitate quantum leap of vacuum or structurual technology to solve. Vacuum pumps and structural tech currently seem pretty well developed so counting on vast improvements here seems risky.
Do you mean improvements are needed to the vacuum pumps, or construction of tubes that can sustain a shallow vacuum? And what specifically is deficient in current structural technology?
Musk has often cautioned that a first principals analysis is much better than the analogy-based approach, which is largely what led him to his work with both Tesla and SpaceX. What is inherently hard about creating large vacuum vessels? These are not ultra high vacuum which requires careful selection of materials, cleaning, baking, multiple stages of vacuum pumps, etc. In fact Hyperloop depends on a rarefied atmosphere for lift, not a full vacuum. The tech, as Musk has stated, is largely similar to pipeline construction, i.e. a steel tube built in sections which are welded together by a robotic welder.
I don't think it's settled either way, but it's risky to make such confident assertions unless you have genuine experience in these fields, which you haven't stated one way or another.